adding back Client-Request-Method to sdk reqs (#20337)

## Description 

Re-merging #20071, as an
optimization to skip parsing jsonrpc request bodies when
`Client-Request-Method` is set

This shouldn't cause any issues now that
#20160 is merged and is running on
testnet and mainnet (via
https://github.com/MystenLabs/sui/tree/releases/sui-v1.38.0-release &
https://github.com/MystenLabs/sui/tree/releases/sui-v1.37.0-release
branches)


## Test plan 

Tested via `pnpm create @mysten/dapp --template react-client-dapp` (ref
#20158) and:
```
curl -v 'https://fullnode.testnet.sui.io/' -X OPTIONS
* Host fullnode.testnet.sui.io:443 was resolved.
[...]
* Request completely sent off
< HTTP/2 200
< access-control-allow-origin: *
< vary: origin, access-control-request-method, access-control-request-headers
< access-control-allow-methods: POST
< access-control-allow-headers: content-type,client-sdk-type,client-sdk-version,client-target-api-version,app-name,client-request-method
```

---

## Release notes

Check each box that your changes affect. If none of the boxes relate to
your changes, release notes aren't required.

For each box you select, include information after the relevant heading
that describes the impact of your changes that a user might notice and
any actions they must take to implement updates.

- [ ] Protocol: 
- [ ] Nodes (Validators and Full nodes): 
- [ ] Indexer: 
- [ ] JSON-RPC: 
- [ ] GraphQL: 
- [ ] CLI: 
- [ ] Rust SDK:
- [ ] REST API:

.changeset/shy-coats-exist.md

@@ -0,0 +1,5 @@
+---
+'@mysten/sui': minor
+---
+
+Adding back 'Client-Request-Method' header

sdk/typescript/src/client/http-transport.ts

@@ -95,6 +95,7 @@ export class SuiHTTPTransport implements SuiTransport {
 				'Client-Sdk-Type': 'typescript',
 				'Client-Sdk-Version': PACKAGE_VERSION,
 				'Client-Target-Api-Version': TARGETED_RPC_VERSION,
+				'Client-Request-Method': input.method,
 				...this.#options.rpc?.headers,
 			},
 			body: JSON.stringify({

sdk/typescript/test/unit/client/http-transport.test.ts

@@ -62,7 +62,7 @@ describe('SuiHTTPTransport', () => {
 					'Client-Sdk-Type': 'typescript',
 					'Client-Sdk-Version': PACKAGE_VERSION,
 					'Client-Target-Api-Version': TARGETED_RPC_VERSION,
-					// 'Client-Request-Method': 'getAllBalances',
+					'Client-Request-Method': 'getAllBalances',
 				},
 				method: 'POST',
 			});